<template>
  <div class="home-page">

    <div class="banner">
      <div class="container">
        <h1 class="logo-font">conduit</h1>
        <p>A place to share your knowledge.</p>
      </div>
    </div>

    <div class="container page">
      <div class="row">

        <div class="col-md-9">
          <div class="feed-toggle">
            <ul class="nav nav-pills outline-active">
              <li class="nav-item"
                  v-if="user">
                <nuxt-link class="nav-link"
                           exact
                           :class="{
                  active:tab === 'your_feed',
                  }"
                           :to="{
                    name:'home',
                    query:{
                        tab:'your_feed'
                    }
                }">Your Feed</nuxt-link>
              </li>
              <li class="nav-item">
                <nuxt-link :to="{
                    name:'home',
                    query:{
                        tab:'global_feed'
                    }
                }"
                           exact
                           :class="{
                    active: tab === 'global_feed'
                  }"
                           class="nav-link">Global Feed</nuxt-link>
              </li>
              <li class="nav-item"
                  v-if="tag">
                <nuxt-link :to="{
                    name:'home',
                    query:{
                        tag:tag,
                        tab:'tag'
                    }
                }"
                           exact
                           :class="{
                    active: tab === 'tag'
                  }"
                           class="nav-link">#{{tag}} </nuxt-link>
              </li>
            </ul>
          </div>

          <nav>
            <ul class="pagination">

              <li class="page-item"
                  :class="{
            active:item === page
        }"
                  v-for="item in totalPage"
                  :key="item">
                <nuxt-link class="page-link"
                           :to="{
                         name:'home',
                         query:{
                            page:item,
                            tag:$route.query.tag,
                            tab:tab
                         }
                     }">{{item}}</nuxt-link>
              </li>

            </ul>
          </nav>
          <div class="article-preview"
               v-for="item in articles"
               :key="item.slug">
            <div class="article-meta">
              <nuxt-link :to="{
                  name:'profile',
                  params:{
                      username:item.author.username
                  }
              }"><img :src="item.author.image" /></nuxt-link>

              <div class="info">
                <nuxt-link :to="{
                  name:'profile',
                  params:{
                      username:item.author.username
                  }
              }"
                           class="author">{{item.author.username}}</nuxt-link>
                <span class="date">{{item.createdAt}}</span>
              </div>
              <button class="btn btn-outline-primary btn-sm pull-xs-right"
                      @click="onFavorite(item)"
                      :class="{
                          active:item.favorited
                      }">
                <i class="ion-heart"></i> {{item.favoritesCount}}
              </button>
            </div>
            <nuxt-link :to="{
                  name:'article',
                  params:{
                      slug:item.slug
                  }
              }"
                       class="preview-link">
              <h1>{{item.title}}</h1>
              <p>{{item.description}}</p>
              <span>Read more...</span>
            </nuxt-link>
          </div>

        </div>

        <div class="col-md-3">
          <div class="sidebar">
            <p>Popular Tags</p>

            <div class="tag-list">
              <nuxt-link v-for="tag in filterTags"
                         :key="tag"
                         :to="{
                             name:'home',
                             query:{
                                 tab:'tag',
                                 tag:tag
                             }
                         }"
                         class="tag-pill tag-default">{{tag}}</nuxt-link>
            </div>
          </div>
        </div>

      </div>
    </div>
  </div>
</template>

<script>
import {
  getArticles,
  getUserArticles,
  getTags,
  deleteFavorite,
  addFavorite,
} from '@/apis'
import { mapState } from 'vuex'

export default {
  name: 'homeIndex',
  // 监听路由变化,触发服务端渲染
  watchQuery: ['page', 'tag', 'tab'],
  computed: {
    ...mapState(['user']),
    totalPage() {
      return Math.ceil(this.articlesCount / this.limit)
    },
    filterTags() {
      return this.tags.filter((v) => v)
    },
  },
  async asyncData({ query }) {
    // 注意：只要这里面报错，页面就渲染不出来，也打印不出问题
    const page = Number.parseInt(query.page || 1)
    const limit = 25
    const tab = query.tab || 'global_feed'
    const tag = query.tag
    const loadArticles = tab === 'global_feed' ? getArticles : getUserArticles

    // 接口并行请求
    const [articleRes, tagRes] = await Promise.all([
      loadArticles({
        // 条数
        limit,
        // 偏移量
        offset: (page - 1) * limit,
        tag,
      }),
      getTags(),
    ])
    const { articles, articlesCount } = articleRes.data

    const { tags } = tagRes.data
    return {
      articles,
      articlesCount,
      tags,
      limit,
      page,
      tab,
      tag,
    }
  },
  data() {
    return {
      favoriteDisabled: false,
    }
  },
  methods: {
    async onFavorite(article) {
      article.favoriteDisabled = true
      if (article.favorited) {
        // 取消点赞
        await deleteFavorite(article.slug)
        article.favorited = false
        article.favoritesCount += -1
      } else {
        // 添加点赞
        await addFavorite(article.slug)
        article.favorited = true
        article.favoritesCount += 1
      }
      article.favoriteDisabled = false
    },
  },
}
</script>

<style>
</style>